Missed vital step

M

Mad Mac

Senior Member
I carry out regular and careful maintenance on my stock 1929 RPU, but somehow, over the years I seem to have missed a vital step. The motor was reconditioned 30 years ago and since then it has faithfully delivered 25,000 miles of trouble-free and enjoyable motoring and still does. The vital missed-step is that I have never re-torqued the head at any time since the motor was fully reconditioning in 1991. I just forgot to do it.

Today I noticed for the first time, oil weeping from the left side head gasket - not large amounts but enough to be concerned about. Obviously I need to gradually re-torque the head to 55 ft lbs as described in other threads. I hope that is all I will have to do - time will tell.

So what is the correct sequence for tightening the head nuts?
 
I did not re-torque on my 29 Tudor for about 30 years. I blew a hose lost the head gasket, had a new. Hose that I didn’t have tight enough .i put about 20,000 miles on it.with no trouble like you I never gave in a thought and never had any trouble.
 
There’s no one correct sequence, either for the order of nuts or the increments of torque. There are a lot of sequences that are fine. It’s more about adhering to general rules.
 
Start in the middle and work your way out. A more specific sequence can be found by googling ford model a head torque sequence
 
I have always used Ford specs for the sequence. I haven’t blown a head gasket in 60 years of driving my A. If it didn’t matter, Ford would not have specified it.
 
The earliest tightening sequence I’ve found published for Model A dates to 1967. If there are “official specs” from ‘28-‘31, I’d be interested to see them. There are plenty of procedures that date from this time, such as the description in Pagé’s book, but they don’t specify a particular sequence.
 
alexiskai said:
The earliest tightening sequence I’ve found published for Model A dates to 1967. If there are “official specs” from ‘28-‘31, I’d be interested to see them. There are plenty of procedures that date from this time, such as the description in Pagé’s book, but they don’t specify a particular sequence.
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Well, you’re right, Colin. I thought I got that from the Service Bulletins, but it isn’t in those. I must have just absorbed it from local guys. The earliest diagram I have in my files is 1973. :o Your point. And now I wonder where that sequence diagram originated!
 
700rpm said:
Well, you’re right, Colin. I thought I got that from the Service Bulletins, but it isn’t in those. I must have just absorbed it from local guys. The earliest diagram I have in my files is 1973. :o Your score.
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If you have the popular How to Restore Your Model A books, then you likely have an earlier one. The diagram on p. 42 of vol. 1 (2nd ed.) is by Fahnestock, and it is a reprint of a diagram published in 1967 in The Restorer as part of a larger article called "Torque Wrenches Prevent Troubles" (Vol. 11 issue 5, pp. 8-10). I know this because of MAFCA's index. I would love to see the text of the article if anyone has it.

We do know that tightening sequences were published for other cars at the time. Dyke's Automobile Encyclopedia printed recommended sequences for the Model T and other early cars. None of these sequences included torque values, of course, since torque wrenches were barely in existence and certainly not in most garages. That's why I've never discounted the possibility that a contemporary sequence for the Model A exists. I've just never seen it.

Despite the Fahnestock diagram postdating the Model A by 35 years, I'm inclined to consider it the next-best thing to factory specs. Murray Fahnestock worked for Ford during the Model A era. He was Technical Editor of their dealer magazine at the time. If anyone knew the official sequence, it would be him.
 
Mad Mac said:
It sure looks like oil, to me. If its coolant have I got a blown head gasket? If so, there is nothing else to indicate it. No strange noise, no loss of power.
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Pull the head down and drive on. The very worst thing that can happen is it blows somewhere down the road but most likely, it will be fine.
 
You can get an oil leak from the head gasket but it is very rare . The crankcase is very slightly pressurised when the engine is under load . Oil mist will pass up the distributer hole and can leak out of the gasket side . I have a car with this situation which it has had for many years. It has never got worse just an oily stain on the block side ."Let sleeping dogs lie" as we say here in Suffolk County .

John in Suffolk County England .
 
Here’s the head bolt torque sequence from my engine rebuilder.
 

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I think you are going to find it is combustion by-product.It will be a little sticky,and maybe have a little brownish tint to it.May smell a little like creosote too.It wicks out through the gasket filler material.There is no oil exposure that high up on the left side of the engine.You can get the same stuff oozing out from around the head studs sometimes.A truly flat head,deck,and torque does prevent it.
 
Thanks everyone for your helpful suggestions. I will torque the head down (using the above sequence) and hope for the best. A friend suggested I turn the head nuts anti-clockwise half a turn before tightening, to avoid breaking the studs. Any comments?
 
Doesn't need to be half a turn, just 20° or so. Just enough to break it loose. Don't loosen all of them at a time, just loosen one, then tighten it, then the next one, etc. It's also typically recommended not to loosen them with the torque wrench because of the risk that the torque required to break it loose may be above the tolerance of the wrench.
 
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